1. Field of the Invention
This invention relates generally to bags having a draw tape. More particularly, the present invention relates generally to trash bags having a draw tape.
2. Description of the Related Art
Among their many applications, it is known to use thermoplastic bags as liners in trash or refuse receptacles. Trash receptacles that employ such liners may be found at many locations, such as, from small household waste baskets and kitchen garbage cans. The trash canisters are typically made from a rigid material such as metal or plastic. Bags that are intended to be used as liners for such refuse containers are typically made from low-cost, pliable thermoplastic material. When the receptacle is full, the thermoplastic liner actually holding the trash can be removed for further disposal and replaced with a new liner. To avoid inadvertently spilling the contents during disposal, the bags may be provided with a draw tape that allows for constricting or closing the open circumference of the bag. The draw tape may also be tied into a knot to simplify handling of the bag during disposal.
Draw tape bags are formed by employing two pliable plastic sheets joined on three sides (or a U-folded plastic sheet joined on two sides) and open on the remaining side. A tubular hem is provided at the open edge of each sheet and contains a cord or pliable thermoplastic strip. One or more access holes are provided in the tubular hem to expose the cord or strip, so as to facilitate pulling the cord or strip through the opening. The action of pulling the cord or strip through the opening results in both closing the open mouth of the bag and formation of a handle whereby the bag may be carried by means of the cord or strip.
Draw tape bags have been commercially available for several years. For example, draw tape or draw cord bags are generally described in U.S. Pat. No. 2,798,523, 3,029,853, 3,506,048 and 3,687,357. A multilayer draw tape is described in U.S. Pat. No. 5,006,380 to Fraser. Fraser addresses the problem of providing a strong draw tape that is still heat sealable to the bag materials by providing a draw tape having a core layer of high density polyethylene with two outer layers of low density polyethylene and low density polyethylene with comonomers such as butene-1, pentene-1, hexene-1, heptene-1, octene-1 and mixtures thereof. The draw tape was produced as a multilayer blown film. Another approach is disclosed in U.S. Pat. App. 2005/0063622 to Kannabiran, where a polymeric blend of materials is used for both strength and sealability.
As is clear from the above discussion, continued technology improvement is needed to address the unique problems associated with the strength of the draw tape and its sealability to relatively thin pliable bag forming materials.